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https://www.readbyqxmd.com/read/28342872/covalent-conjugation-of-the-equine-infectious-anemia-virus-gag-with-sumo
#1
Jinzhong Wang, Shuping Wen, Rui Zhao, Jing Qi, Zhao Liu, Weiwei Li, Jing An, Charles Wood, Ying Wang
The conjugation of small ubiquitin-like modifier (SUMO) to the target protein, namely, SUMOylation, is involved in the regulation of many important biological events including host-pathogen interaction. Some viruses have evolved to exploit the host SUMOylation machinery to modify their own protein. Retroviral Gag protein plays critical roles in the viral life cycle. The HIV-1 p6 and the Moloney murine leukemia virus CA have been reported to be conjugated with SUMO. In this study, we report for the first time, to our knowledge, the covalent conjugation of equine infectious anemia virus (EIAV) Gag with SUMO...
March 22, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28342376/label-free-silicon-nanodots-featured-ratiometric-fluorescent-aptasensor-for-lysosomal-imaging-and-ph-measurement
#2
Yanan Zhang, Shan Guo, Shibo Cheng, Xinghu Ji, Zhike He
The homeostasis of lysosomal pH is crucial in cell physiology. Developing small fluorescent nanosensors for lysosome imaging and ratiometric measurement of pH is highly demanded yet challenging. Herein, a pH-sensitive fluorescein tagged aptamer AS1411 has been utilized to covalently modify the label-free fluorescent silicon nanodots via a crosslinker for construction of a ratiometric pH biosensor. The established aptasensor exhibits the advantages of ultrasmall size, hypotoxicity, excellent pH reversibility and good photostability, which favors its application in an intracellular environment...
March 22, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28339195/the-electronic-configuration-and-ligand-nature-of-five-coordinate-iron-porphyrin-carbene-complexes-an-experimental-study
#3
Yulong Liu, Wei Xu, Jing Zhang, William Fuller, Charles E Schulz, Jianfeng Li
The five coordinate iron porphyrin carbene complexes [Fe(TPP)(CCl<u>2</u>)] (TPP = tetraphenylporphyrin), [Fe(TTP)(CCl<u>2</u>)] (TTP = tetratolylporphyrin) and [Fe(TFPP)(CPh<u>2</u>)] (TFPP = tetra(pentafluorophenyl)porphin), utilizing two types of carbene ligands (CCl<u>2</u> and CPh<u>2</u>), have been investigated by single crystal X-ray, XANES (X-ray Absorption Near Edge Spectroscopy), Mössbauer, NMR and UV-vis spectros-copies. The XANES unambiguously suggested the iron(II) oxida-tion state of the complexes...
March 24, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28339191/allosteric-activation-of-cytochrome-p450-3a4-via-progesterone-bioconjugation
#4
Vanja Polic, Karine Auclair
Human cytochrome P450 3A4 (CYP3A4) is responsible for the metabolism of the majority of drugs. As such, it is implicated in many adverse drug-drug and food-drug interactions, and is of significant interest to the pharmaceutical industry. This enzyme is known to simultaneously bind multiple ligands and display atypical enzyme kinetics, suggestive of allostery and cooperativity. As well, evidence of a postulated peripheral allosteric binding site has provoked debate around its significance and location. We report the use of bioconjugation to study the significance of substrate binding at the proposed allosteric site and its effect on CYP3A4 activity...
March 24, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28339186/quantum-chemical-strain-analysis-for-mechanochemical-processes
#5
Tim Stauch, Andreas Dreuw
The use of mechanical force to initiate a chemical reaction is an efficient alternative to the conventional sources of activation energy, i.e., heat, light, and electricity. Applications of mechanochemistry in academic and industrial laboratories are diverse, ranging from chemical syntheses in ball mills and ultrasound baths to direct activation of covalent bonds using an atomic force microscope. The vectorial nature of force is advantageous because specific covalent bonds can be preconditioned for rupture by selective stretching...
March 24, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28338415/hyaluronic-acid-hydrogel-functionalized-with-self-assembled-micelles-of-amphiphilic-pegylated-kartogenin-for-the-treatment-of-osteoarthritis
#6
Mi-Lan Kang, Se-Young Jeong, Gun-Il Im
Synthetic hyaluronic acid (HA) containing a covalently integrated drug is capable of releasing therapeutic molecules and is an attractive candidate for the intra-articular treatment of osteoarthritis (OA). Herein, self-assembled PEGylated kartogenin (PEG/KGN) micelles consisting of hydrophilic polyethylene glycol (PEG) and hydrophobic KGN, which has been shown to induce chondrogenesis in human mesenchymal stem cells, were prepared by covalent crosslinking. HA hydrogels containing PEG/KGN micelles (HA/PEG/KGN) were prepared by covalently bonding PEG chains to HA...
March 24, 2017: Tissue Engineering. Part A
https://www.readbyqxmd.com/read/28338296/photochromism-and-dual-color-fluorescence-in-a-polyoxometalate-benzospiropyran-molecular-switch
#7
Arnaud Parrot, Aurélie Bernard, Aurélie Jacquart, Stefano Artin Serapian, Carles Bo, Etienne Derat, Olivier Oms, Anne Dolbecq, Anna Proust, Rémi Métivier, Pierre Mialane, Guillaume Izzet
The photophysical properties of a Keggin-type polyoxometalate (POM) covalently bounded to a benzospiropyran (BSPR) unit have been investigated. These studies reveal that both closed and open forms are emissive with distinct spectral features (λem (closed form)=530 nm, λem (open form)=670 nm) and that the fluorescence of the BSPR unit of the hybrid is considerably enhanced compared to BSPR parent compounds. While the fluorescence excitation energy of the BSPR reference compounds (370 nm) is close to the intense absorption responsible of the photochromic character (350 nm), the fluorescence excitation of the hybrid is shifted to lower energy (400 nm), improving the population of the emissive state...
March 24, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28338295/insights-into-the-mechanism-of-a-covalently-linked-organic-dye-cobaloxime-catalyst-system-for-dye-sensitized-solar-fuel-devices
#8
Palas Baran Pati, Lei Zhang, Bertrand Philippe, Ricardo Fernández-Terán, Sareh Ahmadi, Lei Tian, Håkan Rensmo, Leif Hammarström, Haining Tian
A covalently-linked organic dye-cobaloxime catalyst system is developed by facile click reaction for mechanistic studies and application in dye sensitized solar fuel device based on mesoporous NiO. This system has been systematically investigated by photoelectrochemical measurements, density functional theory, time resolved fluorescence, transient absorption spectroscopy as well as photoelectron spectroscopy. The results show that irradiation of the dye-catalyst on NiO leads to ultrafast hole injection into NiO from the excited dye, followed by a fast electron transfer process to reduce the catalyst...
March 24, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28338262/steering-on-surface-reactions-by-a-self-assembly-approach
#9
Qiwei Chen, Jacob R Cramer, Jing Liu, Xin Jin, Peilin Liao, Xiang Shao, Kurt V Gothelf, Kai Wu
4,4'-Bis(2,6-difluoropyridin-4-yl)-1,1':4',1''-terphenyl (BDFPTP) molecules underwent dehydrocyclization and covalent coupling reactions on Au(111) according to scanning tunneling microscopy (STM) measurements and density functional theory (DFT) calculations. Self-assembly of the reactants in well-defined molecular domains prior to reaction could greatly enhance the regioselectivity of the dehydrocyclization reaction and suppress defluorinated coupling, demonstrating that self-assembly can efficiently steer on-surface reactions...
March 24, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28338128/metal-organic-and-covalent-organic-frameworks-as-single-site-catalysts
#10
REVIEW
S M J Rogge, A Bavykina, J Hajek, H Garcia, A I Olivos-Suarez, A Sepúlveda-Escribano, A Vimont, G Clet, P Bazin, F Kapteijn, M Daturi, E V Ramos-Fernandez, F X Llabrés I Xamena, V Van Speybroeck, J Gascon
Heterogeneous single-site catalysts consist of isolated, well-defined, active sites that are spatially separated in a given solid and, ideally, structurally identical. In this review, the potential of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) as platforms for the development of heterogeneous single-site catalysts is reviewed thoroughly. In the first part of this article, synthetic strategies and progress in the implementation of such sites in these two classes of materials are discussed...
March 24, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/28337916/ag-incorporated-organic-inorganic-perovskite-films-and-planar-heterojunction-solar-cells
#11
Qi Chen, Lei Chen, Fengye Ye, Ting Zhao, Feng Tang, Adharsh Rajagopal, Zheng Jiang, Shenlong Jiang, Alex K-Y Jen, Yi Xie, Jinhua Cai, Liwei Chen
Controlled doping for adjustable material polarity and charge carrier concentration is the basis of semiconductor materials and devices, and it is much more difficult to achieve in ionic semiconductors (e.g. ZnO and GaN) than in covalent semiconductors (e.g. Si and Ge), due to the high intrinsic defect density in ionic semiconductors. The organic-inorganic perovskite material, which is frenetically being researched for applications in solar cells and beyond, is also an ionic semiconductor. Here we present the Ag-incorporated organic-inorganic perovskite films and planar heterojunction solar cells...
March 24, 2017: Nano Letters
https://www.readbyqxmd.com/read/28337779/the-chemistry-function-patho-physiology-of-stratum-corneum-barrier-ceramides
#12
REVIEW
David J Moore, Anthony V Rawlings
Research on understanding of the chemistry, function and (patho)physiology of stratum corneum (SC) lipids and especially ceramides has evolved over the last two decades. This has been made successful through the application of separation techniques that have become increasingly more sophisticated and it has become increasingly evident that our understanding of these molecules remains in its infancy. Thirteen classes of ceramides with over 300 and possibly up to 1000 distinct ceramide species have been identified suggesting an exquisitely subtle relationship between the types of ceramides and physical and chemical behavior...
March 24, 2017: International Journal of Cosmetic Science
https://www.readbyqxmd.com/read/28337461/molecular-mechanism-for-the-regulation-of-microcystin-toxicity-to-protein-phosphatase-1-by-glutathione-conjugation-pathway
#13
Wansong Zong, Xiaoning Wang, Yonggang Du, Shuhan Zhang, Ying Zhang, Yue Teng
Glutathione (GSH) conjugation was an important pathway to regulate the toxicity of microcystins (MCs) targeted to protein phosphatases. To explore the specific molecular mechanism for GSH detoxification, two typical MC-GSHs (derived from MCLR and MCRR) were synthesized, prepared, and purified according to previous research. Then, the reduced inhibition effect for MC-GSHs on protein phosphatase 1 was verified by comparing with their original toxins. To further clarify the molecular mechanism for MC-GSHs detoxification, we evaluated the interactions between MCs/MC-GSHs and PP1 with the assistance of MOE molecule simulation...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28337331/light-regulated-no-release-as-a-novel-strategy-to-overcome-doxorubicin-multidrug-resistance
#14
Konstantin Chegaev, Aurore Fraix, Elena Gazzano, Gamal Eldein F Abd-Ellatef, Marco Blangetti, Barbara Rolando, Sabrina Conoci, Chiara Riganti, Roberta Fruttero, Alberto Gasco, Salvatore Sortino
Nitric oxide (NO) release from a suitable NO photodonor (NOP) can be fine-tuned by visible light stimuli at doses that are not toxic to cells but that inhibit several efflux pumps; these are mainly responsible for the multidrug resistance of the anticancer agent doxorubicin (DOX). The strategy may thus increase DOX toxicity against resistant cancer cells. Moreover, a novel molecular hybrid covalently joining DOX and NOP showed similar increased toxicity toward resistant cancer cells and, in addition, lower cardiotoxicity than DOX...
March 9, 2017: ACS Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28337328/structure-activity-relationship-study-of-ql47-a-broad-spectrum-antiviral-agent
#15
Yanke Liang, Melissanne de Wispelaere, Margot Carocci, Qingsong Liu, Jinhua Wang, Priscilla L Yang, Nathanael S Gray
Here we report the structure-activity relationship (SAR) investigations of QL-XII-47 (QL47), a compound that possesses broad-spectrum antiviral activity against dengue virus and other RNA viruses. A medicinal chemistry campaign initiated from QL47, a previously reported covalent BTK inhibitor, to derive YKL-04-085, which is devoid of any kinase activity when screened against a panel of 468 kinases and with improved pharmacokinetic properties. Both QL47 and YKL-04-085 are potent inhibitors of viral translation and exhibit cellular antiviral activity at 35-fold lower concentrations relative to inhibition of host-cell proliferation...
March 9, 2017: ACS Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28337324/discovery-of-gbt440-an-orally-bioavailable-r-state-stabilizer-of-sickle-cell-hemoglobin
#16
Brian Metcalf, Chihyuan Chuang, Kobina Dufu, Mira P Patel, Abel Silva-Garcia, Carl Johnson, Qing Lu, James R Partridge, Larysa Patskovska, Yury Patskovsky, Steven C Almo, Matthew P Jacobson, Lan Hua, Qing Xu, Stephen L Gwaltney, Calvin Yee, Jason Harris, Bradley P Morgan, Joyce James, Donghong Xu, Athiwat Hutchaleelaha, Kumar Paulvannan, Donna Oksenberg, Zhe Li
We report the discovery of a new potent allosteric effector of sickle cell hemoglobin, GBT440 (36), that increases the affinity of hemoglobin for oxygen and consequently inhibits its polymerization when subjected to hypoxic conditions. Unlike earlier allosteric activators that bind covalently to hemoglobin in a 2:1 stoichiometry, 36 binds with a 1:1 stoichiometry. Compound 36 is orally bioavailable and partitions highly and favorably into the red blood cell with a RBC/plasma ratio of ∼150. This partitioning onto the target protein is anticipated to allow therapeutic concentrations to be achieved in the red blood cell at low plasma concentrations...
March 9, 2017: ACS Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28336347/solution-conformations-of-a-linked-construct-of-the-zika-virus-ns2b-ns3-protease
#17
Mithun C Mahawaththa, Benjamin J G Pearce, Bim Graham, Christian D Klein, Christoph Nitsche, Gottfried Otting
The Zika virus presents a serious risk for global health. Crystal structures of different constructs of the Zika virus NS2B-NS3 protease (NS2B-NS3pro) have been determined with the aim to provide a basis for rational drug discovery. In these structures, the C-terminal β-hairpin of NS2B, NS2Bc, was observed to be either disordered (open conformation) or bound to NS3pro complementing the substrate binding site (closed conformation). Enzymatically active constructs of flaviviral NS2B-NS3 proteases commonly used for inhibitor testing contain a covalent peptide linker between NS2B and NS3pro...
March 20, 2017: Antiviral Research
https://www.readbyqxmd.com/read/28335979/microfluidic-immunosensor-based-on-mesoporous-silica-platform-and-cmk-3-poly-acrylamide-co-methacrylate-of-dihydrolipoic-acid-modified-gold-electrode-for-cancer-biomarker-detection
#18
Matías Regiart, Martin A Fernández-Baldo, Jhonny Villarroel-Rocha, Germán A Messina, Franco A Bertolino, Karim Sapag, Aaron T Timperman, Julio Raba
We report a hybrid glass-poly (dimethylsiloxane) microfluidic immunosensor for epidermal growth factor receptor (EGFR) determination, based on the covalent immobilization of anti-EGFR antibody (anti-EGFR) on amino-functionalized mesoporous silica (AMS) retained in the central channel of a microfluidic device. The synthetized AMS was characterized by N2 adsorption-desorption isotherm, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and infrared spectroscopy. The cancer biomarker was quantified in human serum samples by a direct sandwich immunoassay measuring through a horseradish peroxidase-conjugated anti-EGFR...
April 22, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28335973/papain-functionalized-gold-nanoparticles-as-heterogeneous-biocatalyst-for-bioanalysis-and-biopharmaceuticals-analysis
#19
Siyao Liu, Markus Höldrich, Adrian Sievers-Engler, Jeannie Horak, Michael Lämmerhofer
Surface-modified gold nanoparticles (GNPs) were synthesized via layer-by-layer process with alternating cationic polyallylamine and anionic poly(acrylic acid) polyelectrolyte layers leading to a highly hydrophilic biocompatible shell supporting colloidal stability. Afterwards, papain was covalently immobilized on the modified GNPs via amide coupling between the amino groups on papain and the terminal carboxylic groups of the modified GNPs by using N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide and N-hydroxysulfosuccinimide sodium as coupling agents...
April 22, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28335963/copper-chromogenic-reaction-based-colorimetric-immunoassay-for-rapid-and-sensitive-detection-of-a-tumor-biomarker
#20
Bo Li, Guosong Lai, Haili Zhang, Shengli Hu, Aimin Yu
A new colorimetric immunoassay method was developed for the rapid and sensitive detection of a tumor biomarker of carcinoembryonic antigen (CEA) by combination of a magnetic bead (MB)-based sandwich immunoassay and a copper chromogenic reaction. The magnetic immunoassay platform was constructed through the covalent immobilization of the capture antibody on the surface of carboxylated magnetic beads. After immuno-recognition of CEA, signal antibody-functionalized copper oxide nanoparticle (CuO NP) probes were applied for sandwich immunoreaction to form an immunocomplex...
April 22, 2017: Analytica Chimica Acta
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